#VU224 An out-of-bounds access erorr in imagegif/output in PHP - CVE-2016-5095

Vulnerability identifier: #VU224

Vulnerability risk: Low

CVSSv4.0: 2.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2016-5095

CWE-ID: CWE-200

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
PHP
Universal components / Libraries / Scripting languages

Vendor: PHP Group

Description
The vulnerability allows a remote attacker to cause information disclosure.

The vulnerability exists due to error in imagegif/output function in gd_gif_out.c file that causes out-of-bounds read of the masks array when ctx->cur_bits becomes a negative number. A remote unauthenticated attacker can cause an out-of-bounds access erorr in imagegif/output.

Successful exploitation of this vulnerability may result in information disclosure.

Mitigation
Install the latest versions: (5.5.38, 5.6.24, 7.0.9).

Vulnerable software versions

PHP: 5.5.0 - 5.5.37, 5.6.0 - 5.6.23, 7.0.0 - 7.0.8

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External links
https://bugs.php.net/bug.php?id=72519
https://php.net/ChangeLog-5.php#5.5.38
https://php.net/ChangeLog-5.php#5.6.24
https://php.net/ChangeLog-7.php#7.0.9

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.